The present invention relates to an element comprising a substrate with a surface roughness of less than 5 nm, with saturated bonds on the surface and an MPt3 film applied to at least one side of the substrate, with a magnetic anisotropy perpendicular to the plane of the film, and whereby M is selected from a metal of the 5th to 9th sub-group of the periodic table, nickel or gadolinium. The invention further relates to a method for production of the above and the use of said elements as a magnetic component, for example as a magnetic sensor or as a magneto-optical storage element.
Thin alloy films applied onto a substrate are employed, among other things, as magnetic or magneto-optical storage media. In such cases, alloy films of this type meet the requirements to guarantee a high write/read stability and simple manufacturing—especially requirements such as perpendicular magnetic anisotropy, which means: the preferred magnetizing direction is perpendicular to the plane of the film, having 100% remanence, a Curie temperature in the range of 100° C. to 500° C., a suitable temperature dependence of the coercive force. The crystal particles, which form on such films, should have a small grain size therein. The grain size of such crystal particles lies presently at approximately 20 nm.
A possibility to develop storage media with higher storage densities exists, among other things, by reducing the grain size of the film-forming crystal particles, which can lead to a reduction of the bit-storage capacity. However, this causes inevitably problems for thermal stability (superpara magnetic limit) of the stored information and limits the obtainable storage density. Materials having a higher magnetic anisotropy, should nevertheless remain stabile at smaller grain size of the film-forming crystal particles.
Magnetic storage media with a high, perpendicular anisotropy have pertinent advantages compared to traditional storage media with a longitudinal anisotropy such as a stabilization of stored information (bit) against demagnetization and they have thereby a higher storage density.
At the present, there are predominantly materials employed that are formed from ternary systems, as for example CoPtCr alloy systems. However, manufacturing of such systems requires complicated and cost-intensive processing steps, in particular, the thermal activation of individual alloy elements.
Even in binary alloy systems, there can be found good magnetic or magneto-optical properties. Appl. Phys. Lett 69 (8), pages 1166 through 1168, describe, for example, the structural and magnetic properties of FexPt1-x films, which show a large Kerr rotation. Even Co—Pt alloy systems or prior art are distinguished by a large Kerr rotation, for example. Tests of CoPt3(111) alloy films on a Pt(111) nucleus layer produced by molecular beam epitaxy have shown that a long-trajectory, chemically grouped fcc(111) phase (L12 phase) is formed only at a vapor deposition temperature between 550° C. and 700° C. during which all Co atoms occupy the corners of the elementary cell and the Pt atoms are disposed in the plane center. Volume diffusion must be greatly increased through thermal activation, which means a temperature of 550° C. to 700° C. is absolutely necessary to maintain this ordered structure. However, films manufactured in this manner show a longitudinal anisotropy. The preferred perpendicular anisotropy for magnetic application occurs only at vapor deposition temperatures in the range of 200° C. to 400° C. This characteristic is the result of growth-induced processes (segregation tendency).